Distribution of resources for a storage system

ABSTRACT

A method for managing processing power in a storage system is provided. The method includes providing a plurality of blades, each of a first subset having a storage node and storage memory, and each of a second, differing subset having a compute-only node. The method includes distributing authorities across the plurality of blades, to a plurality of nodes including at least one compute-only node, wherein each authority has ownership of a range of user data.

BACKGROUND

Solid-state memory, such as flash, is currently in use in solid-statedrives (SSD) to augment or replace conventional hard disk drives (HDD),writable CD (compact disk) or writable DVD (digital versatile disk)drives, collectively known as spinning media, and tape drives, forstorage of large amounts of data. Flash and other solid-state memorieshave characteristics that differ from spinning media. Yet, manysolid-state drives are designed to conform to hard disk drive standardsfor compatibility reasons, which makes it difficult to provide enhancedfeatures or take advantage of unique aspects of flash and othersolid-state memory.

It is within this context that the embodiments arise.

SUMMARY

In some embodiments, a method for managing processing power in a storagesystem is provided. The method includes providing a plurality of blades,each of a first subset of blades having a storage node and storagememory for storing user data, and each of a second, differing subset ofblades having a compute node (which may be referred to as a compute-onlynode) that may have memory for computing operations. The method includesdistributing authorities across the plurality of blades, to a pluralityof nodes including at least one compute-only node, wherein eachauthority has ownership of a range of user data.

In some embodiments, a tangible, non-transitory, computer-readable mediahaving instructions thereupon which, when executed by a processor, causethe processor to perform a method is provided. The method includesproviding a plurality of blades, each of a first subset having a storagenode and storage memory, and each of a second, differing subset having acompute-only node. The method includes distributing authorities acrossthe plurality of blades, to a plurality of nodes including at least onecompute-only node, wherein each authority has ownership of a range ofuser data.

In some embodiments, a storage system is provided. The system includes aplurality of blades, each of a first subset having a storage node andstorage memory, and each of a second, differing subset having acompute-only node. The system includes the plurality of blades formingthe storage system, wherein authorities are distributed across theplurality of blades, to a plurality of nodes including at least onecompute-only node, and wherein each authority has ownership of a rangeof user data.

Other aspects and advantages of the embodiments will become apparentfrom the following detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the described embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments and the advantages thereof may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings. These drawings in no waylimit any changes in form and detail that may be made to the describedembodiments by one skilled in the art without departing from the spiritand scope of the described embodiments.

FIG. 1 is a perspective view of a storage cluster with multiple storagenodes and internal storage coupled to each storage node to providenetwork attached storage, in accordance with some embodiments.

FIG. 2 is a system diagram of an enterprise computing system, which canuse one or more of the storage clusters of FIG. 1 as a storage resourcein some embodiments.

FIG. 3 is a block diagram showing multiple storage nodes andnon-volatile solid state storage with differing capacities, suitable foruse in the storage cluster of FIG. 1 in accordance with someembodiments.

FIG. 4 is a block diagram showing an interconnect switch couplingmultiple storage nodes in accordance with some embodiments.

FIG. 5 is a multiple level block diagram, showing contents of a storagenode and contents of one of the non-volatile solid state storage unitsin accordance with some embodiments.

FIG. 6 is a diagram of a storage system that uses an embodiment of thestorage cluster of FIGS. 1-5 , with data-owning authorities distributedacross hybrid blades and one or more compute blades.

FIG. 7 is a diagram of the storage system of FIG. 6 showing processingpower distributed across the hybrid blades and compute blade(s) to afront-facing tier for external I/O processing, an authorities tier forthe authorities, and a storage tier for the storage memory.

FIG. 8 is a flow diagram of a method for managing processing power in astorage system, which can be practiced on or by embodiments of thestorage cluster, storage nodes and/or non-volatile solid state storagesin accordance with some embodiments.

FIG. 9 is a flow diagram of a method for managing processing power in astorage system upon addition of a blade, which can be practiced on or byembodiments of the storage cluster, storage nodes and/or non-volatilesolid-state storage is in accordance with some embodiments.

FIG. 10 is an illustration showing an exemplary computing device whichmay implement the embodiments described herein.

DETAILED DESCRIPTION

The embodiments below describe a storage cluster that stores user data,such as user data originating from one or more user or client systems orother sources external to the storage cluster. The storage clusterdistributes user data across storage nodes housed within a chassis,using erasure coding and redundant copies of metadata. Erasure codingrefers to a method of data protection or reconstruction in which data isstored across a set of different locations, such as disks, storage nodesor geographic locations. Flash memory is one type of solid-state memorythat may be integrated with the embodiments, although the embodimentsmay be extended to other types of solid-state memory or other storagemedium, including non-solid state memory. Control of storage locationsand workloads are distributed across the storage locations in aclustered peer-to-peer system. Tasks such as mediating communicationsbetween the various storage nodes, detecting when a storage node hasbecome unavailable, and balancing I/Os (inputs and outputs) across thevarious storage nodes, are all handled on a distributed basis. Data islaid out or distributed across multiple storage nodes in data fragmentsor stripes that support data recovery in some embodiments. Ownership ofdata can be reassigned within a cluster, independent of input and outputpatterns. This architecture described in more detail below allows astorage node in the cluster to fail, with the system remainingoperational, since the data can be reconstructed from other storagenodes and thus remain available for input and output operations. Invarious embodiments, a storage node may be referred to as a clusternode, a blade, or a server. Some embodiments of the storage cluster havehybrid blades, which have storage memory, and compute blades, which donot. Authorities, each of which has ownership of a range of user data,are distributed across hybrid blades, or hybrid blades and computeblades, so as to balance processing power available to each authority ordistribute processing power in accordance with policies, agreements ormulti-tenant service.

The storage cluster is contained within a chassis, i.e., an enclosurehousing one or more storage nodes. A mechanism to provide power to eachstorage node, such as a power distribution bus, and a communicationmechanism, such as a communication bus that enables communicationbetween the storage nodes are included within the chassis. The storagecluster can run as an independent system in one location according tosome embodiments. In one embodiment, a chassis contains at least twoinstances of both the power distribution and the communication bus whichmay be enabled or disabled independently. The internal communication busmay be an Ethernet bus, however, other technologies such as PeripheralComponent Interconnect (PCI) Express, InfiniBand, and others, areequally suitable. The chassis provides a port for an externalcommunication bus for enabling communication between multiple chassis,directly or through a switch, and with client systems. The externalcommunication may use a technology such as Ethernet, InfiniBand, FibreChannel, etc. In some embodiments, the external communication bus usesdifferent communication bus technologies for inter-chassis and clientcommunication. If a switch is deployed within or between chassis, theswitch may act as a translation between multiple protocols ortechnologies. When multiple chassis are connected to define a storagecluster, the storage cluster may be accessed by a client using eitherproprietary interfaces or standard interfaces such as network filesystem (NFS), common internet file system (CIFS), small computer systeminterface (SCSI) or hypertext transfer protocol (HTTP). Translation fromthe client protocol may occur at the switch, chassis externalcommunication bus or within each storage node.

Each storage node may be one or more storage servers and each storageserver is connected to one or more non-volatile solid state memoryunits, which may be referred to as storage units. One embodimentincludes a single storage server in each storage node and between one toeight non-volatile solid state memory units, however this one example isnot meant to be limiting. The storage server may include a processor,dynamic random access memory (DRAM) and interfaces for the internalcommunication bus and power distribution for each of the power buses.Inside the storage node, the interfaces and storage unit share acommunication bus, e.g., PCI Express, in some embodiments. Thenon-volatile solid state memory units may directly access the internalcommunication bus interface through a storage node communication bus, orrequest the storage node to access the bus interface. The non-volatilesolid state memory unit contains an embedded central processing unit(CPU), solid state storage controller, and a quantity of solid statemass storage, e.g., between 2-32 terabytes (TB) in some embodiments. Anembedded volatile storage medium, such as DRAM, and an energy reserveapparatus are included in the non-volatile solid state memory unit. Insome embodiments, the energy reserve apparatus is a capacitor,super-capacitor, or battery that enables transferring a subset of DRAMcontents to a stable storage medium in the case of power loss. In someembodiments, the non-volatile solid state memory unit is constructedwith a storage class memory, such as phase change or magnetoresistiverandom access memory (MRAM) that substitutes for DRAM and enables areduced power hold-up apparatus.

One of many features of the storage nodes and non-volatile solid statestorage is the ability to proactively rebuild data in a storage cluster.The storage nodes and non-volatile solid state storage can determinewhen a storage node or non-volatile solid state storage in the storagecluster is unreachable, independent of whether there is an attempt toread data involving that storage node or non-volatile solid statestorage. The storage nodes and non-volatile solid state storage thencooperate to recover and rebuild the data in at least partially newlocations. This constitutes a proactive rebuild, in that the systemrebuilds data without waiting until the data is needed for a read accessinitiated from a client system employing the storage cluster. These andfurther details of the storage memory and operation thereof arediscussed below.

FIG. 1 is a perspective view of a storage cluster 160, with multiplestorage nodes 150 and internal solid-state memory coupled to eachstorage node to provide network attached storage or storage areanetwork, in accordance with some embodiments. A network attachedstorage, storage area network, or a storage cluster, or other storagememory, could include one or more storage clusters 160, each having oneor more storage nodes 150, in a flexible and reconfigurable arrangementof both the physical components and the amount of storage memoryprovided thereby. The storage cluster 160 is designed to fit in a rack,and one or more racks can be set up and populated as desired for thestorage memory. The storage cluster 160 has a chassis 138 havingmultiple slots 142. It should be appreciated that chassis 138 may bereferred to as a housing, enclosure, or rack unit. In one embodiment,the chassis 138 has fourteen slots 142, although other numbers of slotsare readily devised. For example, some embodiments have four slots,eight slots, sixteen slots, thirty-two slots, or other suitable numberof slots. Each slot 142 can accommodate one storage node 150 in someembodiments. Chassis 138 includes flaps 148 that can be utilized tomount the chassis 138 on a rack. Fans 144 provide air circulation forcooling of the storage nodes 150 and components thereof, although othercooling components could be used, or an embodiment could be devisedwithout cooling components. A switch fabric 146 couples storage nodes150 within chassis 138 together and to a network for communication tothe memory. In an embodiment depicted in FIG. 1 , the slots 142 to theleft of the switch fabric 146 and fans 144 are shown occupied by storagenodes 150, while the slots 142 to the right of the switch fabric 146 andfans 144 are empty and available for insertion of storage node 150 forillustrative purposes. This configuration is one example, and one ormore storage nodes 150 could occupy the slots 142 in various furtherarrangements. The storage node arrangements need not be sequential oradjacent in some embodiments. Storage nodes 150 are hot pluggable,meaning that a storage node 150 can be inserted into a slot 142 in thechassis 138, or removed from a slot 142, without stopping or poweringdown the system. Upon insertion or removal of storage node 150 from slot142, the system automatically reconfigures in order to recognize andadapt to the change. Reconfiguration, in some embodiments, includesrestoring redundancy and/or rebalancing data or load.

Each storage node 150 can have multiple components. In the embodimentshown here, the storage node 150 includes a printed circuit board 158populated by a CPU 156, i.e., processor, a memory 154 coupled to the CPU156, and a non-volatile solid state storage 152 coupled to the CPU 156,although other mountings and/or components could be used in furtherembodiments. The memory 154 has instructions which are executed by theCPU 156 and/or data operated on by the CPU 156. As further explainedbelow, the non-volatile solid state storage 152 includes flash or, infurther embodiments, other types of solid-state memory.

FIG. 2 is a system diagram of an enterprise computing system 102, whichcan use one or more of the storage nodes, storage clusters and/ornon-volatile solid state storage of FIG. 1 as a storage resource 108.For example, flash storage 128 of FIG. 2 may integrate the storagenodes, storage clusters and/or non-volatile solid state storage of FIG.1 in some embodiments. The enterprise computing system 102 hasprocessing resources 104, networking resources 106 and storage resources108, including flash storage 128. A flash controller 130 and flashmemory 132 are included in the flash storage 128. In variousembodiments, the flash storage 128 could include one or more storagenodes or storage clusters, with the flash controller 130 including theCPUs, and the flash memory 132 including the non-volatile solid statestorage of the storage nodes. In some embodiments flash memory 132 mayinclude different types of flash memory or the same type of flashmemory. The enterprise computing system 102 illustrates an environmentsuitable for deployment of the flash storage 128, although the flashstorage 128 could be used in other computing systems or devices, largeror smaller, or in variations of the enterprise computing system 102,with fewer or additional resources. The enterprise computing system 102can be coupled to a network 140, such as the Internet, in order toprovide or make use of services. For example, the enterprise computingsystem 102 could provide cloud services, physical computing resources,or virtual computing services.

In the enterprise computing system 102, various resources are arrangedand managed by various controllers. A processing controller 110 managesthe processing resources 104, which include processors 116 andrandom-access memory (RAM) 118. Networking controller 112 manages thenetworking resources 106, which include routers 120, switches 122, andservers 124. A storage controller 114 manages storage resources 108,which include hard drives 126 and flash storage 128. Other types ofprocessing resources, networking resources, and storage resources couldbe included with the embodiments. In some embodiments, the flash storage128 completely replaces the hard drives 126. The enterprise computingsystem 102 can provide or allocate the various resources as physicalcomputing resources, or in variations, as virtual computing resourcessupported by physical computing resources. For example, the variousresources could be implemented using one or more servers executingsoftware. Files or data objects, or other forms of data, are stored inthe storage resources 108.

In various embodiments, an enterprise computing system 102 could includemultiple racks populated by storage clusters, and these could be locatedin a single physical location such as in a cluster or a server farm. Inother embodiments the multiple racks could be located at multiplephysical locations such as in various cities, states or countries,connected by a network. Each of the racks, each of the storage clusters,each of the storage nodes, and each of the non-volatile solid statestorage could be individually configured with a respective amount ofstorage space, which is then reconfigurable independently of the others.Storage capacity can thus be flexibly added, upgraded, subtracted,recovered and/or reconfigured at each of the non-volatile solid statestorages. As mentioned previously, each storage node could implement oneor more servers in some embodiments.

FIG. 3 is a block diagram showing multiple storage nodes 150 andnon-volatile solid state storage 152 with differing capacities, suitablefor use in the chassis of FIG. 1 . Each storage node 150 can have one ormore units of non-volatile solid state storage 152. Each non-volatilesolid state storage 152 may include differing capacity from othernon-volatile solid state storage 152 on a storage node 150 or in otherstorage nodes 150 in some embodiments. Alternatively, all of thenon-volatile solid state storages 152 on a storage node or on multiplestorage nodes can have the same capacity or combinations of the sameand/or differing capacities. This flexibility is illustrated in FIG. 3 ,which shows an example of one storage node 150 having mixed non-volatilesolid state storage 152 of four, eight and thirty-two TB capacity,another storage node 150 having non-volatile solid state storage 152each of thirty-two TB capacity, and still another storage node havingnon-volatile solid state storage 152 each of eight TB capacity. Variousfurther combinations and capacities are readily devised in accordancewith the teachings herein. In the context of clustering, e.g.,clustering storage to form a storage cluster, a storage node can be orinclude a non-volatile solid state storage 152. Non-volatile solid statestorage 152 is a convenient clustering point as the non-volatile solidstate storage 152 may include a nonvolatile random access memory (NVRAM)component, as will be further described below.

Referring to FIGS. 1 and 3 , storage cluster 160 is scalable, meaningthat storage capacity with non-uniform storage sizes is readily added,as described above. One or more storage nodes 150 can be plugged into orremoved from each chassis and the storage cluster self-configures insome embodiments. Plug-in storage nodes 150, whether installed in achassis as delivered or later added, can have different sizes. Forexample, in one embodiment a storage node 150 can have any multiple of 4TB, e.g., 8 TB, 12 TB, 16 TB, 32 TB, etc. In further embodiments, astorage node 150 could have any multiple of other storage amounts orcapacities. Storage capacity of each storage node 150 is broadcast, andinfluences decisions of how to stripe the data. For maximum storageefficiency, an embodiment can self-configure as wide as possible in thestripe, subject to a predetermined requirement of continued operationwith loss of up to one, or up to two, non-volatile solid state storageunits 152 or storage nodes 150 within the chassis.

FIG. 4 is a block diagram showing a communications interconnect 170 andpower distribution bus 172 coupling multiple storage nodes 150.Referring back to FIG. 1 , the communications interconnect 170 can beincluded in or implemented with the switch fabric 146 in someembodiments. Where multiple storage clusters 160 occupy a rack, thecommunications interconnect 170 can be included in or implemented with atop of rack switch, in some embodiments. As illustrated in FIG. 4 ,storage cluster 160 is enclosed within a single chassis 138. Externalport 176 is coupled to storage nodes 150 through communicationsinterconnect 170, while external port 174 is coupled directly to astorage node. External power port 178 is coupled to power distributionbus 172. Storage nodes 150 may include varying amounts and differingcapacities of non-volatile solid state storage 152 as described withreference to FIG. 3 . In addition, one or more storage nodes 150 may bea compute only storage node as illustrated in FIG. 4 . Authorities 168are implemented on the non-volatile solid state storages 152, forexample as lists or other data structures stored in memory. In someembodiments the authorities are stored within the non-volatile solidstate storage 152 and supported by software executing on a controller orother processor of the non-volatile solid state storage 152. In afurther embodiment, authorities 168 are implemented on the storage nodes150, for example as lists or other data structures stored in the memory154 and supported by software executing on the CPU 156 of the storagenode 150. Authorities 168 control how and where data is stored in thenon-volatile solid state storages 152 in some embodiments. This controlassists in determining which type of erasure coding scheme is applied tothe data, and which storage nodes 150 have which portions of the data.Each authority 168 may be assigned to a non-volatile solid state storage152. Each authority may control a range of inode numbers, segmentnumbers, or other data identifiers which are assigned to data by a filesystem, by the storage nodes 150, or by the non-volatile solid statestorage 152, in various embodiments.

Every piece of data, and every piece of metadata, has redundancy in thesystem in some embodiments. In addition, every piece of data and everypiece of metadata has an owner, which may be referred to as anauthority. If that authority is unreachable, for example through failureof a storage node, there is a plan of succession for how to find thatdata or that metadata. In various embodiments, there are redundantcopies of authorities 168. Authorities 168 have a relationship tostorage nodes 150 and non-volatile solid state storage 152 in someembodiments. Each authority 168, covering a range of data segmentnumbers or other identifiers of the data, may be assigned to a specificnon-volatile solid state storage 152. In some embodiments theauthorities 168 for all of such ranges are distributed over thenon-volatile solid state storages 152 of a storage cluster. Each storagenode 150 has a network port that provides access to the non-volatilesolid state storage(s) 152 of that storage node 150. Data can be storedin a segment, which is associated with a segment number and that segmentnumber is an indirection for a configuration of a RAID (redundant arrayof independent disks) stripe in some embodiments. The assignment and useof the authorities 168 thus establishes an indirection to data.Indirection may be referred to as the ability to reference dataindirectly, in this case via an authority 168, in accordance with someembodiments. A segment identifies a set of non-volatile solid statestorage 152 and a local identifier into the set of non-volatile solidstate storage 152 that may contain data. In some embodiments, the localidentifier is an offset into the device and may be reused sequentiallyby multiple segments. In other embodiments the local identifier isunique for a specific segment and never reused. The offsets in thenon-volatile solid state storage 152 are applied to locating data forwriting to or reading from the non-volatile solid state storage 152 (inthe form of a RAID stripe). Data is striped across multiple units ofnon-volatile solid state storage 152, which may include or be differentfrom the non-volatile solid state storage 152 having the authority 168for a particular data segment.

If there is a change in where a particular segment of data is located,e.g., during a data move or a data reconstruction, the authority 168 forthat data segment should be consulted, at that non-volatile solid statestorage 152 or storage node 150 having that authority 168. In order tolocate a particular piece of data, embodiments calculate a hash valuefor a data segment or apply an inode number or a data segment number.The output of this operation points to a non-volatile solid statestorage 152 having the authority 168 for that particular piece of data.In some embodiments there are two stages to this operation. The firststage maps an entity identifier (ID), e.g., a segment number, inodenumber, or directory number to an authority identifier. This mapping mayinclude a calculation such as a hash or a bit mask. The second stage ismapping the authority identifier to a particular non-volatile solidstate storage 152, which may be done through an explicit mapping. Theoperation is repeatable, so that when the calculation is performed, theresult of the calculation repeatably and reliably points to a particularnon-volatile solid state storage 152 having that authority 168. Theoperation may include the set of reachable storage nodes as input. Ifthe set of reachable non-volatile solid state storage units changes theoptimal set changes. In some embodiments, the persisted value is thecurrent assignment (which is always true) and the calculated value isthe target assignment the cluster will attempt to reconfigure towards.This calculation may be used to determine the optimal non-volatile solidstate storage 152 for an authority in the presence of a set ofnon-volatile solid state storage 152 that are reachable and constitutethe same cluster. The calculation also determines an ordered set of peernon-volatile solid state storage 152 that will also record the authorityto non-volatile solid state storage mapping so that the authority may bedetermined even if the assigned non-volatile solid state storage isunreachable. A duplicate or substitute authority 168 may be consulted ifa specific authority 168 is unavailable in some embodiments.

With reference to FIGS. 1-4 , two of the many tasks of the CPU 156 on astorage node 150 are to break up write data, and reassemble read data.When the system has determined that data is to be written, the authority168 for that data is located as above. When the segment ID for data isalready determined the request to write is forwarded to the non-volatilesolid state storage 152 currently determined to be the host of theauthority 168 determined from the segment. The host CPU 156 of thestorage node 150, on which the non-volatile solid state storage 152 andcorresponding authority 168 reside, then breaks up or shards the dataand transmits the data out to various non-volatile solid state storage152. The transmitted data is written as a data stripe in accordance withan erasure coding scheme. In some embodiments, data is requested to bepulled, and in other embodiments, data is pushed. In reverse, when datais read, the authority 168 for the segment ID containing the data islocated as described above. The host CPU 156 of the storage node 150 onwhich the non-volatile solid state storage 152 and correspondingauthority 168 reside requests the data from the non-volatile solid statestorage and corresponding storage nodes pointed to by the authority. Insome embodiments the data is read from flash storage as a data stripe.The host CPU 156 of storage node 150 then reassembles the read data,correcting any errors (if present) according to the appropriate erasurecoding scheme, and forwards the reassembled data to the network. Infurther embodiments, some or all of these tasks can be handled in thenon-volatile solid state storage 152. In some embodiments, the segmenthost requests the data be sent to storage node 150 by requesting pagesfrom storage and then sending the data to the storage node making theoriginal request.

In some systems, for example in UNIX-style file systems, data is handledwith an index node or inode, which specifies a data structure thatrepresents an object in a file system. The object could be a file or adirectory, for example. Metadata may accompany the object, as attributessuch as permission data and a creation timestamp, among otherattributes. A segment number could be assigned to all or a portion ofsuch an object in a file system. In other systems, data segments arehandled with a segment number assigned elsewhere. For purposes ofdiscussion, the unit of distribution is an entity, and an entity can bea file, a directory or a segment. That is, entities are units of data ormetadata stored by a storage system. Entities are grouped into setscalled authorities. Each authority has an authority owner, which is astorage node that has the exclusive right to update the entities in theauthority. In other words, a storage node contains the authority, andthat the authority, in turn, contains entities.

A segment is a logical container of data in accordance with someembodiments. A segment is an address space between medium address spaceand physical flash locations, i.e., the data segment number, are in thisaddress space. Segments may also contain meta-data, which enable dataredundancy to be restored (rewritten to different flash locations ordevices) without the involvement of higher level software. In oneembodiment, an internal format of a segment contains client data andmedium mappings to determine the position of that data. Each datasegment is protected, e.g., from memory and other failures, by breakingthe segment into a number of data and parity shards, where applicable.The data and parity shards are distributed, i.e., striped, acrossnon-volatile solid state storage 152 coupled to the host CPUs 156 (SeeFIG. 5 ) in accordance with an erasure coding scheme. Usage of the termsegments refers to the container and its place in the address space ofsegments in some embodiments. Usage of the term stripe refers to thesame set of shards as a segment and includes how the shards aredistributed along with redundancy or parity information in accordancewith some embodiments.

A series of address-space transformations takes place across an entirestorage system. At the top is the directory entries (file names) whichlink to an inode. Inodes point into medium address space, where data islogically stored. Medium addresses may be mapped through a series ofindirect mediums to spread the load of large files, or implement dataservices like deduplication or snapshots. Medium addresses may be mappedthrough a series of indirect mediums to spread the load of large files,or implement data services like deduplication or snapshots. Segmentaddresses are then translated into physical flash locations. Physicalflash locations have an address range bounded by the amount of flash inthe system in accordance with some embodiments. Medium addresses andsegment addresses are logical containers, and in some embodiments use a128 bit or larger identifier so as to be practically infinite, with alikelihood of reuse calculated as longer than the expected life of thesystem. Addresses from logical containers are allocated in ahierarchical fashion in some embodiments. Initially, each non-volatilesolid state storage 152 may be assigned a range of address space. Withinthis assigned range, the non-volatile solid state storage 152 is able toallocate addresses without synchronization with other non-volatile solidstate storage 152.

Data and metadata is stored by a set of underlying storage layouts thatare optimized for varying workload patterns and storage devices. Theselayouts incorporate multiple redundancy schemes, compression formats andindex algorithms. Some of these layouts store information aboutauthorities and authority masters, while others store file metadata andfile data. The redundancy schemes include error correction codes thattolerate corrupted bits within a single storage device (such as a NANDflash chip), erasure codes that tolerate the failure of multiple storagenodes, and replication schemes that tolerate data center or regionalfailures. In some embodiments, low density parity check (LDPC) code isused within a single storage unit. Reed-Solomon encoding is used withina storage cluster, and mirroring is used within a storage grid in someembodiments. Metadata may be stored using an ordered log structuredindex (such as a Log Structured Merge Tree), and large data may not bestored in a log structured layout.

In order to maintain consistency across multiple copies of an entity,the storage nodes agree implicitly on two things through calculations:(1) the authority that contains the entity, and (2) the storage nodethat contains the authority. The assignment of entities to authoritiescan be done by pseudorandomly assigning entities to authorities, bysplitting entities into ranges based upon an externally produced key, orby placing a single entity into each authority. Examples of pseudorandomschemes are linear hashing and the Replication Under Scalable Hashing(RUSH) family of hashes, including Controlled Replication Under ScalableHashing (CRUSH). In some embodiments, pseudo-random assignment isutilized only for assigning authorities to nodes because the set ofnodes can change. The set of authorities cannot change so any subjectivefunction may be applied in these embodiments. Some placement schemesautomatically place authorities on storage nodes, while other placementschemes rely on an explicit mapping of authorities to storage nodes. Insome embodiments, a pseudorandom scheme is utilized to map from eachauthority to a set of candidate authority owners. A pseudorandom datadistribution function related to CRUSH may assign authorities to storagenodes and create a list of where the authorities are assigned. Eachstorage node has a copy of the pseudorandom data distribution function,and can arrive at the same calculation for distributing, and laterfinding or locating an authority. Each of the pseudorandom schemesrequires the reachable set of storage nodes as input in some embodimentsin order to conclude the same target nodes. Once an entity has beenplaced in an authority, the entity may be stored on physical devices sothat no expected failure will lead to unexpected data loss. In someembodiments, rebalancing algorithms attempt to store the copies of allentities within an authority in the same layout and on the same set ofmachines.

Examples of expected failures include device failures, stolen machines,datacenter fires, and regional disasters, such as nuclear or geologicalevents. Different failures lead to different levels of acceptable dataloss. In some embodiments, a stolen storage node impacts neither thesecurity nor the reliability of the system, while depending on systemconfiguration, a regional event could lead to no loss of data, a fewseconds or minutes of lost updates, or even complete data loss.

In the embodiments, the placement of data for storage redundancy isindependent of the placement of authorities for data consistency. Insome embodiments, storage nodes that contain authorities do not containany persistent storage. Instead, the storage nodes are connected tonon-volatile solid state storage units that do not contain authorities.The communications interconnect between storage nodes and non-volatilesolid state storage units consists of multiple communicationtechnologies and has non-uniform performance and fault tolerancecharacteristics. In some embodiments, as mentioned above, non-volatilesolid state storage units are connected to storage nodes via PCIexpress, storage nodes are connected together within a single chassisusing Ethernet backplane, and chassis are connected together to form astorage cluster. Storage clusters are connected to clients usingEthernet or fiber channel in some embodiments. If multiple storageclusters are configured into a storage grid, the multiple storageclusters are connected using the Internet or other long-distancenetworking links, such as a “metro scale” link or private link that doesnot traverse the internet.

Authority owners have the exclusive right to modify entities, to migrateentities from one non-volatile solid state storage unit to anothernon-volatile solid state storage unit, and to add and remove copies ofentities. This allows for maintaining the redundancy of the underlyingdata. When an authority owner fails, is going to be decommissioned, oris overloaded, the authority is transferred to a new storage node.Transient failures make it non-trivial to ensure that all non-faultymachines agree upon the new authority location. The ambiguity thatarises due to transient failures can be achieved automatically by aconsensus protocol such as Paxos, hot-warm failover schemes, via manualintervention by a remote system administrator, or by a local hardwareadministrator (such as by physically removing the failed machine fromthe cluster, or pressing a button on the failed machine). In someembodiments, a consensus protocol is used, and failover is automatic. Iftoo many failures or replication events occur in too short a timeperiod, the system goes into a self-preservation mode and haltsreplication and data movement activities until an administratorintervenes in accordance with some embodiments.

As authorities are transferred between storage nodes and authorityowners update entities in their authorities, the system transfersmessages between the storage nodes and non-volatile solid state storageunits. With regard to persistent messages, messages that have differentpurposes are of different types. Depending on the type of the message,the system maintains different ordering and durability guarantees. Asthe persistent messages are being processed, the messages aretemporarily stored in multiple durable and non-durable storage hardwaretechnologies. In some embodiments, messages are stored in RAM, NVRAM andon NAND flash devices, and a variety of protocols are used in order tomake efficient use of each storage medium. Latency-sensitive clientrequests may be persisted in replicated NVRAM, and then later NAND,while background rebalancing operations are persisted directly to NAND.

Persistent messages are persistently stored prior to being transmitted.This allows the system to continue to serve client requests despitefailures and component replacement. Although many hardware componentscontain unique identifiers that are visible to system administrators,manufacturer, hardware supply chain and ongoing monitoring qualitycontrol infrastructure, applications running on top of theinfrastructure address virtualize addresses. These virtualized addressesdo not change over the lifetime of the storage system, regardless ofcomponent failures and replacements. This allows each component of thestorage system to be replaced over time without reconfiguration ordisruptions of client request processing.

In some embodiments, the virtualized addresses are stored withsufficient redundancy. A continuous monitoring system correlateshardware and software status and the hardware identifiers. This allowsdetection and prediction of failures due to faulty components andmanufacturing details. The monitoring system also enables the proactivetransfer of authorities and entities away from impacted devices beforefailure occurs by removing the component from the critical path in someembodiments.

FIG. 5 is a multiple level block diagram, showing contents of a storagenode 150 and contents of a non-volatile solid state storage 152 of thestorage node 150. Data is communicated to and from the storage node 150by a network interface controller (NIC) 202 in some embodiments. Eachstorage node 150 has a CPU 156, and one or more non-volatile solid statestorage 152, as discussed above. Moving down one level in FIG. 5 , eachnon-volatile solid state storage 152 has a relatively fast non-volatilesolid state memory, such as nonvolatile random access memory (NVRAM)204, and flash memory 206. In some embodiments, NVRAM 204 may be acomponent that does not require program/erase cycles (DRAM, MRAM, PCM),and can be a memory that can support being written vastly more oftenthan the memory is read from. Moving down another level in FIG. 5 , theNVRAM 204 is implemented in one embodiment as high speed volatilememory, such as dynamic random access memory (DRAM) 216, backed up byenergy reserve 218. Energy reserve 218 provides sufficient electricalpower to keep the DRAM 216 powered long enough for contents to betransferred to the flash memory 206 in the event of power failure. Insome embodiments, energy reserve 218 is a capacitor, super-capacitor,battery, or other device, that supplies a suitable supply of energysufficient to enable the transfer of the contents of DRAM 216 to astable storage medium in the case of power loss. The flash memory 206 isimplemented as multiple flash dies 222, which may be referred to aspackages of flash dies 222 or an array of flash dies 222. It should beappreciated that the flash dies 222 could be packaged in any number ofways, with a single die per package, multiple dies per package (i.e.multichip packages), in hybrid packages, as bare dies on a printedcircuit board or other substrate, as encapsulated dies, etc. In theembodiment shown, the non-volatile solid state storage 152 has acontroller 212 or other processor, and an input output (I/O) port 210coupled to the controller 212. I/O port 210 is coupled to the CPU 156and/or the network interface controller 202 of the flash storage node150. Flash input output (I/O) port 220 is coupled to the flash dies 222,and a direct memory access unit (DMA) 214 is coupled to the controller212, the DRAM 216 and the flash dies 222. In the embodiment shown, theI/O port 210, controller 212, DMA unit 214 and flash I/O port 220 areimplemented on a programmable logic device (PLD) 208, e.g., a fieldprogrammable gate array (FPGA). In this embodiment, each flash die 222has pages, organized as sixteen kB (kilobyte) pages 224, and a register226 through which data can be written to or read from the flash die 222.In further embodiments, other types of solid-state memory are used inplace of, or in addition to flash memory illustrated within flash die222.

Storage cluster 160, in various embodiments as disclosed herein, can becontrasted with storage arrays in general. The storage nodes 150 arepart of a collection that creates the storage cluster 160. Each storagenode 150 owns a slice of data and computing required to provide thedata. Multiple storage nodes 150 cooperate to store and retrieve thedata. Storage memory or storage devices, as used in storage arrays ingeneral, are less involved with processing and manipulating the data.Storage memory or storage devices in a storage array receive commands toread, write, or erase data. The storage memory or storage devices in astorage array are not aware of a larger system in which they areembedded, or what the data means. Storage memory or storage devices instorage arrays can include various types of storage memory, such as RAM,solid state drives, hard disk drives, etc. The non-volatile solid statestorage 152 described herein have multiple interfaces activesimultaneously and serving multiple purposes. In some embodiments, someof the functionality of a storage node 150 is shifted into non-volatilesolid state storage 152, transforming the non-volatile solid statestorage 152 into a combination of non-volatile solid state storage 152and storage node 150. Placing computing (relative to storage data) intothe non-volatile solid state storage 152 places this computing closer tothe data itself. The various system embodiments have a hierarchy ofstorage node layers with different capabilities. By contrast, in astorage array, a controller owns and knows everything about all of thedata that the controller manages in a shelf or storage devices. In astorage cluster 160, as described herein, multiple controllers inmultiple non-volatile solid state storage units 152 and/or storage nodes150 cooperate in various ways (e.g., for erasure coding, data sharding,metadata communication and redundancy, storage capacity expansion orcontraction, data recovery, and so on).

FIG. 6 is a diagram of a storage system that uses an embodiment of thestorage cluster 160 of FIGS. 1-5 , with data-owning authorities 168distributed across hybrid blades 602 and one or more compute blades 604.Blades are physical constructs, with circuitry, processor(s), andassorted hardware. Each hybrid blade 602 has storage memory for storinguser data, which is flash memory 206 in this embodiment but could beother types of storage memory in further embodiments, and processingresources, including the CPU 156 and DRAM 216. Each compute blade 604has processing resources, including a CPU 156 and DRAM 216, but, unlikea hybrid blades 602, does not have storage memory for storing user data.That is, unlike the hybrid blade 602, the compute blade 604 does notstore user data on the compute blade 604 itself. Hybrid blades 602 andcompute blades 604 could have other types of memory, such as ROM(read-only memory) for program memory, or could use the DRAM 216 orother type of RAM for program memory and operating parameters, i.e.,system memory. Each blade 602, 604 has a network module 606 (see, e.g.,network interface controller 202 of FIG. 5 ), and the blades 602, 604are coupled together to form the storage cluster 160. All user data isstored in storage memory on the hybrid blades 602, as described withreference to FIGS. 1-5 . Usage of various numbers of hybrid blades 602or a mixture of hybrid blades 602 and compute blades 604 in a storagesystem allows the amount of storage memory and processing power to betailored to system and client needs, and allows replacements andupgrades in each or both of these aspects of system performance.

As in the embodiments of the storage cluster 160 in FIGS. 1-5 , eachblade 602, 604 can host or be a storage node 150, in the sense that allof the blades 602, 604 participate in at least some of the operations ofthe storage cluster 160. Nodes are logical constructs in a storagesystem, and are responsible for the behavior, intelligence, protocols,etc. in the storage system. A node can reside in a blade and make use ofthe physical resources in the physical blade. A hybrid blade 602 is orhas therein a storage node with storage memory, and a compute blade 604is or has therein a compute-only node without storage memory. That is, astorage node 150 on a hybrid blade 602 can use both of the computingresources and the storage memory on the hybrid blade 602, and storagememory on other hybrid blades 602, in reading and writing user data andperforming other storage node tasks. A compute-only node on a computeblade 604 can use the computing resources on the compute blade 604, butmay use storage memory on hybrid blades 602, as the compute blade 604lacks storage memory. A compute-only node on a compute blade 604 usesthe computing resources (including local memory, e.g., ROM and DRAM 216)on the compute blade 604, but performs computing tasks, not the storagetasks performed by the storage nodes 150, and so does not use storagememory on any of the hybrid blades 604 in the same manner that thestorage nodes 150 would. There may be applications where a compute-onlynode could access storage memory on hybrid blades 602, for example fordiagnostics, repair, or other purposes or functions outside of the usualtasks of a storage node 150. A compute-only node as described herein maybe referred to as a compute node in some embodiments. Authorities 168can reside in any storage node and thus can reside in hybrid blades 602and/or compute blades 604. Each storage node can hold one or moreauthorities 168. Each authority 168 owns a range of user data, which isnon-overlapping with the range of user data owned by any other authority168, and selects and controls the erasure coding and placement of thatrange of user data independent of other authorities 168. In the exampleshown in FIG. 6 , the left-most hybrid blade 602 has four authorities168, the right-most hybrid blade 602 has four authorities 168, theleft-most compute blade 604 has two authorities 168, and the right-mostcompute blade 604 has four authorities 168. This is by example only, andeach of the blades 602, 604 could have various numbers of authorities168, which need not be the same in each of the blades 602, 604.

Authorities 168 can be moved from one blade 602, 604 to another blade602, 604 in various numbers and directions. In this example in FIG. 6 ,one of the authorities 168 is moved from the left-most hybrid blade 602to the left-most compute blade 604, but could instead be moved to theright-most compute blade 604 (or any other compute blade 604 in thesystem, or to another hybrid blade 602). One of the authorities 168 ismoved from the right-most hybrid blade 602 to the left-most computeblade 604. An authority on a compute blade 604 could similarly be movedto another compute blade 604 or to a hybrid blade 602, etc.

Various mechanisms for locating and/or moving an authority 168 can bedeveloped by the person skilled in the art in keeping with the presentteachings. For example, authorities 168 are shown in DRAM 216 in thevarious blades 602, 604. In some embodiments, various parameters, maps,accountings, records, pointers, etc., and/or a data structureimplementing an authority 168 is resident in a DRAM 216 of one of theblades 602, 604, and could be moved by copying this information from theDRAM 216 of one blade 602, 604 to the DRAM 216 of another blade 602,604. Software code that is executed to perform the actions of theauthority 168 could be resident in the DRAM 216 and similarly moved.Alternatively, software code could be resident in another memory, suchas a non-volatile memory, or firmware of the blade 602, 604, andexecuted by the CPU 156 but activated or deactivated according to one ormore parameters or one or more execution threads in a multi-threadingsystem. In one embodiment, various parameters of an authority 168 aremoved from one blade 602, 604 to another blade 602, 604, and thesoftware code in memories in each of the blades 602, 604 operates inaccordance with the parameters of the authorities 168 that are residentin memory in the blades 602, 604.

Blades and 602, 604 can have differing amounts of computing orprocessing power, processing characteristics or computing resources. Forexample, different models or versions of a product may be offered, orlater versions may have newer, faster, denser processors or memories, ormore numerous processor cores 608, etc. In one example, one CPU 156 hasfour cores 608, as shown in the left-most compute blade 604, and anotherCPU 156 has eight cores 608, as shown in the right-most compute blade604. One CPU 156 could have a faster clock speed than another. One DRAM216 could have more megabytes, gigabytes or terabytes than another, or afaster access time. These factors can affect hybrid blades 602 andcompute blades 604. Adding even a single compute blade 604 to a storagecluster 160 that has two or more hybrid blades 602 can boost performanceof the system, and adding two or more compute blades 602 can boost theperformance further. A heterogeneous system, with some number of hybridblades 602 that have both storage and compute resources, and anothernumber of compute blades 604 that have compute-only nodes, could bebalanced differently than a homogeneous system with only hybrid blades602. The embodiments could take advantage of the computing power orresources that is on the compute-only nodes, which do not have todedicate any computing power or resources to storage on that same blade604. It is worth noting that adding too many authorities 168 to astorage system that is processing limited will likely decreaseperformance. Adding authorities 168 (e.g., to handle a greater totalamount of data) while also adding processing power 720 (e.g., by addingone or more hybrid blades 602 and/or compute blades 604) scales thesystem so as to preserve performance at a given level. Other examplesare readily devised.

FIG. 7 is a diagram of the storage system of FIG. 6 showing processingpower 720 distributed across the hybrid blades 602 and compute blade(s)604 to a front-facing tier 714 for external I/O processing, anauthorities tier 716 for the authorities 168, and a storage tier 718 forthe storage memory (e.g., flash memory 206 or other type of storagememory). By distributing processing power 720, it is meant that work,processing tasks, computing, computing tasks, processing or computingactivity, I/O processing (external or internal), etc., is arranged,dedicated, assigned, provided for, scheduled, allocated, made available,etc., to the devices and processes in the various tiers 714, 716, 718.For example, distributing processing power 720 to the front-facing tier714 means that the resources in the front-facing tier 714 can performexternal I/O processing with a portion of the processing power 720.Distributing processing power 720 to the authorities tier 716 means thatthe authorities 168 can perform duties specific to the authorities 168with a portion of the processing power 720. Distributing processingpower 720 to the storage tier 718 means that the devices and processesin the storage tier 718 can perform storage duties with a portion of theprocessing power 720. While this example discusses various tiers, thisis not meant to be limiting as this example is one example utilized forillustrative purposes. Processing power can be distributed by assigningprocesses or threads to specific processors or vice versa, arrangingpriorities of processes or threads, and in further ways readily devisedin computing systems.

Multiple tenants 702 are making I/O requests, which the storage cluster160 is handling and servicing as external I/O processing 704. Variouspolicies and agreements 706, 708, 710 are in place in the storagesystem. Processing power 720 across the hybrid blade(s) 602, when thereare no compute blades 604 in the system, or across the hybrid blade(s)602 and compute blade(s) 604 when both types of blades 602, 604 arepresent in the system, is distributed to the operations tiers 712, e.g.the front-facing tier 714, the authorities tier 716 and the storage tier718. It should be appreciated that this can happen in various ways,combinations and scenarios as described below.

Dedicated to receiving requests from clients for external I/O, thefront-facing tier 714 decodes I/O requests and figures out where dorequests go, i.e., to which authority 168 should each request be sent.This involves various calculations and maps, and takes a portion of theprocessing power 720. In some embodiments, an I/O request from a client,for external I/O processing, could be received in any storage node,i.e., any hybrid blade 602 or any compute blade 604. In someembodiments, I/O requests could be routed to specific blade or blades602, 604. External I/O request processing and throughput in theseembodiments is determined in accordance with the distribution ofprocessing power 720 to the front-facing tier 714.

Next down from the front-facing tier 714, the authorities tier 716performs the various tasks the authorities 168 require. Behavior of thesystem at the authorities tier 716 is as if each authority 168 is avirtual controller or processor, and this takes a further portion of theprocessing power 720. Distribution of the processing power 720 to and inthe authorities tier 716 could be done on a per authority 168 or perblade 602, 604 basis, in various embodiments, and could be equally orevenly distributed across the authorities 168 or varied across theauthorities 168 in a given blade 602, 604.

Below the authorities tier 716, the storage tier 718 takes care of tasksfor which the storage memory is responsible, which takes another portionof the processing power 720. Further computing power for the storagememory is available in each of the storage units 152, e.g., from thecontroller 212. How the processing power is distributed to each of thetiers 714, 716, 718, and how the processing power is distributed withina given tier 714, 716, 718 is flexible and can be determined by thestorage cluster 160 and/or by a user, e.g., an administrator.

In one scenario, there are initially only hybrid blades 602 in a storagecluster 160, and one or more compute blades 604 are added, for exampleas an upgrade or improvement. This adds to the processing power 720available to the system. Although, in this scenario, the total amount ofstorage memory does not change (since no hybrid blades 602 with storagememory are added), the total of number of processors and the totalamount of processing power 720 in the system is increased as a result ofadding the compute blade(s) 604. Authorities 168 can be distributed, orredistributed, according to how much processing power 720 is availableon each blade 602, 604. For example, if all of the CPUs 156 areequivalent in processing speed and number of cores 608, each of theblades 602, 604 could receive an equal number of authorities 168. Insome embodiments, if one of the blades, be it a hybrid blade 602 orcompute blade 604, has a more powerful processor (i.e., more processingpower 720), that blade 602, 604 could be assigned a greater number ofauthorities 168. One way to distribute authorities 168 is to assign orallocate authorities to each blade 602, 604 in proportion to therelative amount of processing power 720 on that blade 602, 604. Doing sobalances the processing power 720 across the authorities 168 such thateach authority 168 has a comparable amount of processing power 720accessible to that authority 168 on the blade 602, 604 on which theauthority 168 resides. This can entail either adding new authorities 168to one or more of the blades 602, 604, or moving one or more authorities168 from one blade 602, 604 to another blade 602, 604. Referring back tothe embodiment and example shown in FIG. 6 , this could be the case whenone or more compute blades 604 are added to the storage cluster, whichtriggers relocation of one or more authorities 168.

In a related scenario, the authorities are assigned, distributed,redistributed or relocated to the various blades 602, 604 in proportionto the amount of DRAM 206 (or other type of RAM or memory), or theperformance of the DRAM 206 (e.g., read and write access speeds)available on each of the blades 602, 604. A blade 602, 604 with agreater amount of DRAM 206 would then receive or have a larger number ofauthorities than a blade 602, 604 with a lesser amount of DRAM 206.Doing so balances the RAM across the authorities 168 such that eachauthority 168 as a comparable amount of RAM accessible to the authority168 on the blade 602, 604 on which the authority 168 resides.

In another scenario, portions of the total amount of the processingpower 720 in all of the blades 602, 604 of a storage cluster 160 aredistributed to the operations tiers 712 in accordance with quality ofservice (QOS) policies 706, service level agreements 708, serviceclasses and/or multi-tenant service 710. For example, if a policy,agreement or service class is to provide a greater level of external I/Oprocessing, e.g., a higher data throughput to and/or from data storageto one tenant 702, class of service, IP address or range of IPaddresses, range of data, type of data, etc., than another, then agreater amount of processing power 720 is allocated to that tenant 702,class of service, etc., as compared to other tenants 702, classes ofservice, etc., in the front-facing tier 714 and/or in the authoritiestier 716. Computing tasks of external I/O processing can be distributedacross the blades 602, 604 so that I/O processing for each tenant 702,class of service, etc., is assigned to one or more storage nodes, whichcould reside on hybrid blades 602 and/or compute blades 604 in variouscombinations, on an individual tenant, client, application, serviceclass, etc., basis. Computing tasks for applications in an applicationlayer (i.e., application software distinct from the software thatoperates the storage cluster 160) could be distributed across one ormore of the blades 602, 604, on a basis of individual applications orgroups of applications and individual blades or groups of blades 602,604, in various combinations. For example, computing tasks for one setof applications could be assigned to one group of blades 602, 604, andcomputing tasks for another set of applications could be assigned toanother group of blades 602, 604, and these could be overlapping ornon-overlapping groups. Authorities 168 for the inodes of data belongingto a tenant 702, class of service, etc., could be assigned a greaterproportion of the processor cores 608, weighted by clock frequency orprocessor speed, as compared to other tenants 702, classes of service,etc., for example by moving authorities 168 appropriately. The systemcould balance how much processing power 720 is available for theauthorities 168 versus the storage memory, for example by controllingthe number of threads launched or weighting the threads as to priority.Amount of storage guaranteed to a tenant 702 and quality of service(e.g., throughput, latency, responsiveness) can be adjusted orthogonally(i.e., independently), on a steady, elastic, or demand basis in thesystem. In some embodiments, heuristics can be applied to measuring andadjusting these and other aspects of the system. Changes to policies,agreements, or tenants could also trigger relocation of one or moreauthorities 168.

FIG. 8 is a flow diagram for a method of managing processing power in astorage system. The method can be practiced on or by various embodimentsof a storage cluster and storage nodes as described herein. Varioussteps of the method can be performed by a processor, such as a processorin a storage cluster or a processor in a storage node. Portions or allof the method can be implemented in software, hardware, firmware orcombinations thereof. The method initiates with action 802, in whichhybrid blades are provided. Each hybrid blade includes a storage nodeand storage memory. In an action 804, compute blades are provided. Eachcompute blade includes a compute-only node and no storage memory. Thecompute blade has system memory, such as DRAM or other RAM, but does nothave solid-state storage memory or disk-based storage memory on thecompute blade itself. Authorities are distributed across the blades, inan action 806. That is, authorities are located on, moved to orotherwise established on the hybrid blades and compute blades.

In an action 808, processing power is distributed across the blades to atier, e.g., a front-facing tier, an authorities tier, and a storagetier, according to agreements and/or policies as mentioned above.Depending on what is in the agreements or policies, processing powercould be distributed to each of the tiers in fixed or variable amounts.The front-facing tier services external I/O requests, i.e., is forexternal I/O processing, the authorities tier is for servicing theauthorities, and the storage tier is for servicing the storage memory inthis embodiment.

In an action 810, external I/O processing is performed in thefront-facing tier, and internal I/O processing (i.e., processing ofinternal I/O operations relating to various resources in the storagesystem) is performed in the authorities tier and the storage tier. In adecision action 812, the question is asked, should processing power beredistributed in the authorities tier? If the answer is no, there is noneed to redistribute processing power in the authorities tier, flowbranches back to the action 810, to continue performing external andinternal I/O processing. If the answer is yes, processing power is to beredistributed in the authorities tier, flow proceeds to the action 814.This could be triggered, for example, by insertion of a compute bladeinto the storage cluster, insertion of a hybrid blade, or changes topolicies, agreements or multi-tenant service.

In the action 814, an authority is moved from one blade to another blade(e.g., a hybrid blade to a compute blade, a hybrid blade to anotherhybrid blade, a compute blade to another compute blade, or even from acompute blade to a hybrid blade). In some embodiments more than oneauthority is moved among the blades. In a variation, processing poweramong the tiers, or within one of the tiers, could be redistributed inresponse to changes in agreements or policies, or insertion of a blade.Flow then returns to the action 810, to continue performing external andinternal I/O processing. In variations, flow could proceed elsewhere toperform further actions.

FIG. 9 is a flow diagram of a method for managing processing power in astorage system upon addition of a blade, which can be practiced on or byembodiments of the storage cluster, storage nodes and/or non-volatilesolid-state storages in accordance with some embodiments. The method isrelated to that of FIG. 8 , and in variations could be combined with orreplace portions of the method described with reference to FIG. 8 . Themethod begins with a decision action 902, in which it is determinedwhether to add a blade to the storage system. If the answer is no, noblade should be or is added, the method may wait for a period of timeand check if a blade is to be added in some embodiments. If the answeris yes, a blade is added, flow proceeds to the decision action 904. Inthe decision action 904, is determined whether the newly added blade isto participate in the authorities tier. For example, it could be decidedthat the newly added blade will have a compute-only node, but does notparticipate in the authorities tier. Or, it could be decided that thenewly added blade will have a compute-only storage node, and participatein actions performed by or on behalf of authorities as participation inthe authorities tier. If the answer is no, the newly added blade is notto participate in the authorities tier, flow proceeds to the decisionaction 902. If the answer is yes, the newly added blade is toparticipate in the authorities tier, flow proceeds to the decisionaction 906.

In the decision action 906, it is determined whether to move newauthorities to the newly added blade. If the answer is yes, flowproceeds to the action 908, in which new authorities are moved or addedto the newly added blade. As mentioned above the movement of authoritiesfrom one or more blades to one or more further blades will redistributethe processing power as desired. Flow branches back to the action 902,to see if a blade is being added or will be added. In variations, flowcould branch elsewhere to perform further tasks. In the case where thedecision action 904 determined that the newly added blade is not toparticipate in the authorities tier, the newly added blade could beexcluded from receiving any of the moved authorities, or the decisioncould be revisited, in which case the newly added blade could receiveone or more of the moved authorities. After authorities are moved, flowproceeds back to the action 902, or in variations, branches elsewhere toperform further tasks.

It should be appreciated that the methods described herein may beperformed with a digital processing system, such as a conventional,general-purpose computer system. Special purpose computers, which aredesigned or programmed to perform only one function may be used in thealternative. FIG. 10 is an illustration showing an exemplary computingdevice which may implement the embodiments described herein. Thecomputing device of FIG. 10 may be used to perform embodiments of thefunctionality for the managing processing power in a storage system inaccordance with some embodiments. The computing device includes acentral processing unit (CPU) 1001, which is coupled through a bus 1005to a memory 1003, and mass storage device 1007. Mass storage device 1007represents a persistent data storage device such as a floppy disc driveor a fixed disc drive, which may be local or remote in some embodiments.Memory 1003 may include read only memory, random access memory, etc.Applications resident on the computing device may be stored on oraccessed via a computer readable medium such as memory 1003 or massstorage device 1007 in some embodiments. Applications may also be in theform of modulated electronic signals modulated accessed via a networkmodem or other network interface of the computing device. It should beappreciated that CPU 1001 may be embodied in a general-purposeprocessor, a special purpose processor, or a specially programmed logicdevice in some embodiments.

Display 1011 is in communication with CPU 1001, memory 1003, and massstorage device 1007, through bus 1005. Display 1011 is configured todisplay any visualization tools or reports associated with the systemdescribed herein. Input/output device 1009 is coupled to bus 1005 inorder to communicate information in command selections to CPU 1001. Itshould be appreciated that data to and from external devices may becommunicated through the input/output device 1009. CPU 1001 can bedefined to execute the functionality described herein to enable thefunctionality described with reference to FIGS. 1-9 . The code embodyingthis functionality may be stored within memory 1003 or mass storagedevice 1007 for execution by a processor such as CPU 1001 in someembodiments. The operating system on the computing device may be MSDOS™, MS-WINDOWS™, OS/2™, UNIX™, LINUX™, or other known operatingsystems. It should be appreciated that the embodiments described hereinmay also be integrated with a virtualized computing system implementedwith physical computing resources.

Detailed illustrative embodiments are disclosed herein. However,specific functional details disclosed herein are merely representativefor purposes of describing embodiments. Embodiments may, however, beembodied in many alternate forms and should not be construed as limitedto only the embodiments set forth herein.

It should be understood that although the terms first, second, etc. maybe used herein to describe various steps or calculations, these steps orcalculations should not be limited by these terms. These terms are onlyused to distinguish one step or calculation from another. For example, afirst calculation could be termed a second calculation, and, similarly,a second step could be termed a first step, without departing from thescope of this disclosure. As used herein, the term “and/or” and the “/”symbol includes any and all combinations of one or more of theassociated listed items.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”,“comprising”, “includes”, and/or “including”, when used herein, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. Therefore, the terminology usedherein is for the purpose of describing particular embodiments only andis not intended to be limiting.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

With the above embodiments in mind, it should be understood that theembodiments might employ various computer-implemented operationsinvolving data stored in computer systems. These operations are thoserequiring physical manipulation of physical quantities. Usually, thoughnot necessarily, these quantities take the form of electrical ormagnetic signals capable of being stored, transferred, combined,compared, and otherwise manipulated. Further, the manipulationsperformed are often referred to in terms, such as producing,identifying, determining, or comparing. Any of the operations describedherein that form part of the embodiments are useful machine operations.The embodiments also relate to a device or an apparatus for performingthese operations. The apparatus can be specially constructed for therequired purpose, or the apparatus can be a general-purpose computerselectively activated or configured by a computer program stored in thecomputer. In particular, various general-purpose machines can be usedwith computer programs written in accordance with the teachings herein,or it may be more convenient to construct a more specialized apparatusto perform the required operations.

A module, an application, a layer, an agent or other method-operableentity could be implemented as hardware, firmware, or a processorexecuting software, or combinations thereof. It should be appreciatedthat, where a software-based embodiment is disclosed herein, thesoftware can be embodied in a physical machine such as a controller. Forexample, a controller could include a first module and a second module.A controller could be configured to perform various actions, e.g., of amethod, an application, a layer or an agent.

The embodiments can also be embodied as computer readable code on anon-transitory computer readable medium. The computer readable medium isany data storage device that can store data, which can be thereafterread by a computer system. Examples of the computer readable mediuminclude hard drives, network attached storage (NAS), read-only memory,random-access memory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes, and otheroptical and non-optical data storage devices. The computer readablemedium can also be distributed over a network coupled computer system sothat the computer readable code is stored and executed in a distributedfashion. Embodiments described herein may be practiced with variouscomputer system configurations including hand-held devices, tablets,microprocessor systems, microprocessor-based or programmable consumerelectronics, minicomputers, mainframe computers and the like. Theembodiments can also be practiced in distributed computing environmentswhere tasks are performed by remote processing devices that are linkedthrough a wire-based or wireless network.

Although the method operations were described in a specific order, itshould be understood that other operations may be performed in betweendescribed operations, described operations may be adjusted so that theyoccur at slightly different times or the described operations may bedistributed in a system which allows the occurrence of the processingoperations at various intervals associated with the processing.

In various embodiments, one or more portions of the methods andmechanisms described herein may form part of a cloud-computingenvironment. In such embodiments, resources may be provided over theInternet as services according to one or more various models. Suchmodels may include Infrastructure as a Service (IaaS), Platform as aService (PaaS), and Software as a Service (SaaS). In IaaS, computerinfrastructure is delivered as a service. In such a case, the computingequipment is generally owned and operated by the service provider. Inthe PaaS model, software tools and underlying equipment used bydevelopers to develop software solutions may be provided as a serviceand hosted by the service provider. SaaS typically includes a serviceprovider licensing software as a service on demand. The service providermay host the software, or may deploy the software to a customer for agiven period of time. Numerous combinations of the above models arepossible and are contemplated.

Various units, circuits, or other components may be described or claimedas “configured to” perform a task or tasks. In such contexts, the phrase“configured to” is used to connote structure by indicating that theunits/circuits/components include structure (e.g., circuitry) thatperforms the task or tasks during operation. As such, theunit/circuit/component can be said to be configured to perform the taskeven when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. 112, sixth paragraph, for that unit/circuit/component.Additionally, “configured to” can include generic structure (e.g.,generic circuitry) that is manipulated by software and/or firmware(e.g., an FPGA or a general-purpose processor executing software) tooperate in manner that is capable of performing the task(s) at issue.“Configured to” may also include adapting a manufacturing process (e.g.,a semiconductor fabrication facility) to fabricate devices (e.g.,integrated circuits) that are adapted to implement or perform one ormore tasks.

The foregoing description, for the purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings. Theembodiments were chosen and described in order to best explain theprinciples of the embodiments and its practical applications, to therebyenable others skilled in the art to best utilize the embodiments andvarious modifications as may be suited to the particular usecontemplated. Accordingly, the present embodiments are to be consideredas illustrative and not restrictive, and the invention is not to belimited to the details given herein, but may be modified within thescope and equivalents of the appended claims.

What is claimed is:
 1. A storage system, comprising: a plurality ofblades; a plurality of storage nodes distributed across the plurality ofblades; and a plurality of authorities distributed across the pluralityof storage nodes, each authority of the plurality of authorities owninga range of data stored in the system, the plurality of authoritiesdistributed across the plurality of storage in proportion to an amountof processing power on each of the plurality of blades.
 2. The system ofclaim 1, wherein the storage nodes are contained within multiplechassis.
 3. The system of claim 1, wherein the plurality of bladescomprise storage nodes and compute only nodes.
 4. The system of claim 1,wherein an I/O request received for the external I/O processing isrouted from one of the storage nodes to another one of the storagenodes, in accordance with the plurality of authorities.
 5. The system ofclaim 1, wherein at least one of the plurality of authorities isrelocatable from one of the storage nodes to another of the storagenodes.
 6. The system of claim 1, wherein the plurality of storage nodesincludes at least one compute node.
 7. The system of claim 1, whereinprocessing power for external I/O processing is distributed inaccordance with one or more policies, agreements, service classes ormulti-tenant services.
 8. The system of claim 1, wherein the storagesystem is a multi-tenant storage system.
 9. The storage nodes of claim1, wherein the system balances an amount of power allotted to theplurality of authorities and the storage nodes.
 10. A storage cluster,comprising: a plurality of blades; a plurality of storage nodesdistributed across the plurality of blades; at least one compute node;and a plurality of authorities distributed across the plurality ofstorage nodes, each authority of the plurality of authorities owning arange of data stored in the system, the plurality of authoritiesdistributed across the plurality of storage in proportion to an amountof processing power on each of the plurality of blades.
 11. The storagecluster of claim 10, wherein the plurality of storage nodes arecontained within multiple chassis.
 12. The storage cluster of claim 10,wherein the storage memory of one of the plurality of storage nodescomprises differing types of storage memory having differing capacities.13. The storage cluster of claim 12, wherein the distributed processingpower is configurable for routing an I/O request, received for externalI/O processing, from one of the plurality of storage nodes to adiffering one of the plurality of storage nodes, in accordance with theplurality of authorities.
 14. The storage cluster of claim 12, whereinthe distributed processing power is configurable for moving one or moreof the plurality of authorities from one of the plurality of storagenodes to a differing one of the plurality of storage nodes.
 15. Thestorage cluster of claim 12, wherein the plurality of authorities aredistributed across the plurality of storage in proportion to an amountof memory on each of the plurality of blades
 16. The storage cluster ofclaim 12, wherein the distributed processing power for external I/Oprocessing is allocatable in accordance with one or more policies,agreements, service classes or multi-tenant service.
 17. The storagecluster of claim 10, wherein the at least one compute node isparticipating in actions on behalf of authorities.
 18. The system ofclaim 1, wherein the storage memory of one of the plurality of storagenodes comprises differing types of storage memory having differingcapacities.
 19. A method, comprising: providing a plurality of blades,each including a storage node and storage memory; and distributingauthorities across the plurality of blades in proportion to one of anamount of memory or an amount of processing power of each of theplurality of blades.
 20. The method of claim 19, further comprising:adding a compute-only node; and re-distributing the authorities acrossthe plurality of blades and the compute-only node.